AMNION
AMOXICILLIN
AMNIOCENTESIS
disorders
such as
haemophilia, cystic
fibrosis,
and
Tay-Sachs disease.
Chemi-
cal analysis of amniotic fluid can help
to diagnose developmental abnorm-
alities such as
spina bifida. Rhesus
incompatibility
and maturity of the fetal
lungs can also be checked.
Amniocentesis is usually performed in
the 14th- 18th week of pregnancy. It
slightly increases the risk of
miscarriage
or early rupture of the membranes and is
therefore recommended only when the
fetus is thought to be at increased risk
of an abnormality. (See also
antenatal
care, chorionic villus sampling. )
amnion
One of the membranes that
surrounds the
fetus
in the
uterus.
The
outside of the amnion is covered by
another membrane called the
chorion.
amniotic fluid
The clear, watery fluid
(popularly called the "waters") that sur-
rounds the
fetus
in the
uterus.
The fluid
is contained within the
amniotic sac.
It
cushions the fetus, allowing movement.
Amniotic fluid is produced by cells lin-
ing the amniotic sac and is constantly
circulated. It appears in the 1st week
after
conception
and
gradually
in-
creases in volume until the 10th week,
when the increase becomes very rapid.
Occasionally, excessive fluid is formed
(see
polyhydramnios);
less frequently,
insufficient amniotic fluid is formed
(see
oligohydramnios).
amniotic sac
The membranous bag that
surrounds the
fetus
and is filled with
amniotic fluid
as pregnancy advances.
The sac is made up of 2 membranes, the
inner
amnion
and the outer
chorion.
amniotomy
Artificial rupture of the am-
niotic membranes (breaking the "waters")
performed for
induction o f labour.
amoeba
A type of protozoon (see
proto-
zoa).
An
amoeba is a
microscopic
single-celled organism with an irregular,
changeable shape. Amoebae live in
moist environments,
such
as
fresh
water and soil. Some types of amoebae
are parasites of humans, causing dis-
eases such as
amoebiasis.
amoebiasis
An infection caused by the
amoeba
entamoeba histolytica,
a tiny
single-celled parasite that lives in the
human large intestine. Amoebiasis is
spread through drinking water or eating
food contaminated by human excreta
containing cysts of the amoeba.
Some people carry the amoeba in their
intestines and excrete cysts but have no
symptoms. However, some strains in-
vade and ulcerate the intestinal wall,
causing diarrhoea and abdominal pain,
which
may develop into full-blown
dysentery.
The amoebae may spread via
the bloodstream to the liver, or, rarely,
the brain or lung, where they cause
abscesses. Symptoms of an amoebic
liver abscess are chills, fever, weight
loss, and painful enlargement of the liver.
Treatment of all forms of amoebiasis
is with drugs such as
metronidazole
or
diloxanide, which kill the parasite with-
in a few weeks, leading to full recovery,
amoebic dysentery
See
amoebiasis.
amoebicides
A group of drugs used to
treat
amoebiasis.
Examples are dilox-
anide, and
metronidazole.
amoxapine
An
antidepressant drug
re-
lated to the tricyclics. Possible adverse
effects include blurred vision, dizziness,
drowsiness, abnormal muscular move-
ments,
menstrual
irregularities,
and
breast enlargement.
amoxicillin
A
penicillin drug
commonly
used to treat a variety of infections,
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